The study will assess how the inhalation technique used (deep inhalations versus tidal breathing) influences the results of a mannitol challenge test and a methacholine challenge test, if at all.
This study will look at airway responsiveness to inhaled methacholine and mannitol administered with and without deep inhalation. This study will also investigate the role of airway inflammation on these responses, using sputum differential cell counts and fractional exhaled nitric oxide. This is a single center, open label, randomized study. Individuals with stable asthma will be eligible for enrollment. The study will consist of two parts, screening and testing. Part 1: Screening Participants will undergo consent procedures and assessments of fractional exhaled nitric oxide levels, airway responsiveness to methacholine and sputum induction. If participants show airway responsiveness to methacholine (i.e. methacholine PC20 16mg/mL), they will be scheduled to undergo the testing part of the study. Part 2: Testing Participants will be randomized to undergo two methacholine or two mannitol challenges. Further randomization will occur with respect to whether the standard challenge method or the modified challenge method is performed first.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
26
Use of deep inhalations for administration of inhalant
Use of tidal breathing for administration of inhalant
Methacholine direct bronchoconstrictor used for bronchoprovocation challenge
Asthma Research Lab - University of Saskatchewan
Saskatoon, Saskatchewan, Canada
Effect of deep inhalation (versus tidal breathing) on mannitol provocative dose causing a 15% fall in forced expiratory volume in one second (FEV1)
Shift in mannitol provocative dose causing a 15% fall in forced expiratory volume
Time frame: 24 hours between mannitol challenges
Effect of airway inflammation on methacholine and mannitol challenge results-fractional exhaled nitric oxide
Collection of fractional exhaled nitric oxide at screening - analysis of resulting measurement indicative of degree of baseline airway inflammation
Time frame: up to 2 weeks, from baseline to end of study
Effect of airway inflammation on methacholine and mannitol challenge results-sputum
Collection of sputum at screening - analysis for differential cell counts indicative of degree of baseline airway inflammation
Time frame: up to 2 weeks, from baseline to end of study
Effect of deep inhalation (versus tidal breathing) on methacholine provocative
Shift in methacholine provocative dose causing a 20% fall in forced expiratory volume
Time frame: 24 hours between methacholine challenges
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Mannitol indirect bronchoconstrictor used for bronchoprovocation challenge